Description
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On MyISAM, Aria and InnoDB tables, MariaDB can create spatial indexes (an
R-tree index) using syntax similar to that for creating regular indexes, but
extended with the SPATIAL keyword. Currently, columns in spatial indexes must
be declared NOT NULL.

Spatial indexes can be created when the table is created, or added after the
fact like so:

* with CREATE TABLE: CREATE TABLE geom (g GEOMETRY NOT NULL, SPATIAL INDEX(g));

* with ALTER TABLE: ALTER TABLE geom ADD SPATIAL INDEX(g);

* with CREATE INDEX: CREATE SPATIAL INDEX sp_index ON geom (g);

SPATIAL INDEX creates an R-tree index. For storage engines that support
non-spatial indexing of spatial columns, the engine creates a B-tree index. A
B-tree index on spatial values is useful for exact-value lookups, but not for
range scans.

For more information on indexing spatial columns, see CREATE INDEX.

To drop spatial indexes, use ALTER TABLE or DROP INDEX:

* with ALTER TABLE: ALTER TABLE geom DROP INDEX g;

* with DROP INDEX: DROP INDEX sp_index ON geom;

Data-at-Rest Encyption
----------------------

Before MariaDB 10.4.3, InnoDB's spatial indexes could not be encrypted. If an
InnoDB table was encrypted and if it contained spatial indexes, then those
indexes would be unencrypted.

In MariaDB 10.4.3 and later, if innodb_checksum_algorithm is set to full_crc32
or strict_full_crc32, and if the table does not use ROW_FORMAT=COMPRESSED,
then InnoDB spatial indexes will be encrypted if the table is encrypted.

See MDEV-12026 for more information.

URL: https://mariadb.com/kb/en/spatial-index/